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Sugahara T, Hashizume D, Tokitoh N, Matsui H, Kishi R, Nakano M, Sasamori T. Characterization of resonance structures in aromatic rings of benzene and its heavier-element analogues. Phys Chem Chem Phys 2022; 24:22557-22561. [PMID: 36000346 DOI: 10.1039/d2cp03068c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present the experimental visualization of the valence-electron-density distribution in benzene and its kinetically stabilized heavier-element analogues, i.e., 1,2-disilabenzene and 1,2-digermabenzene. The valence-electron-density-distribution (EDD) analysis on the 1,2-disila- and 1,2-digermabenzenes revealed that these contain incompletely delocalized π electrons on their cyclic conjugation systems, making them less aromatic compared to benzene. Based on the results of this EDD analysis in combination with anisotropy of the current-induced density (ACID) calculations, considerable contributions from the characteristic resonance structures of 1,2-disila- and 1,2-digermabenzenes with cleaved EE bonds can be expected.
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Affiliation(s)
- Tomohiro Sugahara
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Daisuke Hashizume
- RIKEN Center for Emergent Matter Science (CEMS), 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Norihiro Tokitoh
- Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan
| | - Hiroshi Matsui
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Ryohei Kishi
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.,Research Center for Solar Energy Chemistry (RCSEC) and Center for Quantum Information and Quantum Biology (QIQB) Osaka University, Toyonaka, Osaka 560-8531, Japan.,Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Masayoshi Nakano
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Takahiro Sasamori
- Division of Chemistry, Faculty of Pure and Applied Sciences, and Tsukuba Research Center for Energy Materials Science (TREMS), University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8571, Japan.
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2
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Varandas AJC. From six to eight Π-electron bare rings of group-XIV elements and beyond: can planarity be deciphered from the "quasi-molecules" they embed? Phys Chem Chem Phys 2022; 24:8488-8507. [PMID: 35343978 DOI: 10.1039/d1cp04130d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ab initio molecular orbital theory is used to study the structures of six and eight π-electron bare rings of group-XIV elements, and even larger [n]annulenes up to C18H18, including some of their mono-, di-, tri-, and tetra-anions. While some of the above rings are planar, others are nonplanar. A much spotlighted case is cyclo-octatetraene (C8H8), which is predicted to be nonplanar together with its heavier group-XIV analogues Si8H8 and Ge8H8, with the solely planar members of its family having the stoichiometric formulas C4Si4H8 and C4Ge4H8. A similar situation arises with the six π-electron bare rings, where benzene and substituted ones up to C3Si3H6 or so are planar, while others are not. However, the explanations encountered in the literature find support in ab initio calculations for such species, often rationalized from distinct calculated features. Using second-order Møller-Plesset perturbation theory and, when affordable (particularly tetratomics, which may allow even higher levels), the coupled-cluster method including single, double, and perturbative triple excitations, a common rationale is suggested based on a novel concept of quasi-molecules or the (3+4)-atom partition scheme. Any criticism of tautology is therefore avoided. The same analysis has also been successfully applied to even larger [n]annulenes, to their mixed family members involving silicon and germanium atoms, and to the C18 carbon ring. Furthermore, it has been extended to annulene anions to check the criteria of the popular Hückel rule for planarity and aromaticity. Exploratory work on cycloarenes is also reported. Besides a partial study of the involved potential energy surfaces, equilibrium geometries and harmonic vibrational frequencies have been calculated anew, for both the parent and the actual prototypes of the quasi-molecules.
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Affiliation(s)
- A J C Varandas
- School of Physics and Physical Engineering, Qufu Normal University, 273165 Qufu, China.,Department of Physics, Universidade Federal do Esp rito Santo, 29075-910 Vitória, Brazil.,Department of Chemistry, and Chemistry Centre, University of Coimbra, 3004-535 Coimbra, Portugal.
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Kroeger AA, Karton A. Graphene-induced planarization of cyclooctatetraene derivatives. J Comput Chem 2022; 43:96-105. [PMID: 34677827 DOI: 10.1002/jcc.26774] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 09/10/2021] [Accepted: 10/08/2021] [Indexed: 11/09/2022]
Abstract
Stable equilibrium compounds containing a planar antiaromatic cyclooctatetraene (COT) ring are promising candidates for organic electronic devices such as organic semiconductor transistors. The planarization of COT by incorporation into rigid planar π-systems, as well as by oxidation or reduction has attracted considerable attention in recent years. Using dispersion-corrected density functional theory calculations, we explore an alternative approach of planarizing COT derivatives by adsorption onto graphene. We show that strong π-π stacking interactions between graphene and COT derivatives induce a planar structure with an antiaromatic central COT ring. In addition to being reversible, this strategy provides a novel approach for planarizing COT without the need for incorporation into a rigid structure, atomic substitution, oxidation, or reduction.
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Affiliation(s)
- Asja A Kroeger
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
| | - Amir Karton
- School of Molecular Sciences, The University of Western Australia, Perth, Australia
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Planar ten-membered 10-π-electron aromatic (CH) 5(XH) 5 {X = Ge, Sn} systems. J Mol Model 2018; 24:264. [PMID: 30171368 DOI: 10.1007/s00894-018-3797-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/14/2018] [Indexed: 10/28/2022]
Abstract
Being monocyclic planar, benzene retains 6π Hückel aromatic backbone. However, for larger analogues, the repulsion between vicinal C-H bonds makes them nonplanar, as for [10]-annulene. Thus, on this basis, a planar 10-π-aromatic C10H10 is unreachable. A detailed structural comparison among the C3H3+, C4H42+, C5H5-, C6H6, C7H7+, C8H82+, C9H9-, and C10H10 systems supports that the repulsion between vicinal C-H bonds is the primary reason for the loss of planarity, despite the favorable aromatic electron count. In this respect, here we have discussed ten-membered monocyclic planar 10-π-aromatic, (CH)5(XH)5 {X = Si, Ge, Sn} systems, modeled by using DFT. From NBO analysis and the overall magnetic behavior it is shown that (CH)5(GeH)5, (CH)5(SnH)5 molecules are promising planar 10-π-aromatic system. Thus, such species represent plausible Hückel aromatic rings retaining a ten-membered backbone as discussed here, which may lead to the characterization of novel species expanding the chemistry of larger aromatic rings. We believe that the present study may open new avenues in the formation of 10-π-aromatic species. Graphical abstract Molecular modeling in quest of a planar 10-membered 10-π-electron aromatic system.
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Srivastava AK, Misra N. Introducing “carborazine” as a novel heterocyclic aromatic species. NEW J CHEM 2015. [DOI: 10.1039/c4nj02089h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aromatic carborazine is a heterocyclic ring consisting of C, B and N atoms at opposite faces.
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Affiliation(s)
| | - Neeraj Misra
- Department of Physics
- University of Lucknow
- Lucknow-226007
- India
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Sánchez-Sanz G, Trujillo C, Rozas I, Alkorta I. Influence of fluoro and cyano substituents in the aromatic and antiaromatic characteristics of cyclooctatetraene. Phys Chem Chem Phys 2015; 17:14961-71. [DOI: 10.1039/c5cp00876j] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
An exhaustive and systematic study of the structural and electronic properties of cyclooctatetraene (COT) upon substitution of hydrogen atoms by fluoro and cyano groups has been carried out in order to analyse the influence of both substituents on the aromaticity.
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Affiliation(s)
- Goar Sánchez-Sanz
- School of Physics & Complex and Adaptive Systems Laboratory
- University College Dublin
- Dublin 4
- Ireland
| | - Cristina Trujillo
- School of Chemistry
- Trinity Biomedical Sciences Institute
- Trinity College Dublin
- Dublin 2
- Ireland
| | - Isabel Rozas
- School of Chemistry
- Trinity Biomedical Sciences Institute
- Trinity College Dublin
- Dublin 2
- Ireland
| | - Ibon Alkorta
- Instituto de Química Médica
- CSIC
- E-28006 Madrid
- Spain
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Jalife S, Audiffred M, Islas R, Escalante S, Pan S, Chattaraj PK, Merino G. The inorganic analogues of carbo -benzene. Chem Phys Lett 2014. [DOI: 10.1016/j.cplett.2014.07.038] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Islas R, Poater J, Solà M. Analysis of the Aromaticity of Five-Membered Heterometallacycles Containing Os, Ru, Rh, and Ir. Organometallics 2014. [DOI: 10.1021/om500119c] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Rafael Islas
- Institut
de Química Computacional i Catàlisi and Departament
de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Catalonia, Spain
- Departamento
de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta s/n, Guanajuato, C.P. 36050, México
| | - Jordi Poater
- Institut
de Química Computacional i Catàlisi and Departament
de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Catalonia, Spain
| | - Miquel Solà
- Institut
de Química Computacional i Catàlisi and Departament
de Química, Universitat de Girona, Campus Montilivi, 17071 Girona, Catalonia, Spain
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Tang SW, Wang FD, Li YH, Wang F, Yang SB, Sun H, Chang YF, Wang RS. From pure C₃₆ fullerene to cagelike nanocluster: a density functional study. J Mol Model 2013; 19:5579-86. [PMID: 24257902 DOI: 10.1007/s00894-013-2039-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Accepted: 10/18/2013] [Indexed: 11/25/2022]
Abstract
The geometrical structures, energetics properties, and aromaticity of C(₃₆-n) Si(n) (n ≤ 18) fullerene-based clusters were studied using density functional theory calculations. The geometries of C(₃₆-n) Si(n) clusters undergo strong structural deformation with the increase of Si substitution. For the most energy favorable structures of C(₃₆-n) Si(n) , the silicon and carbon atoms form two distinct homogeneous segregations. Subsequently, the binding energy, HOMO-LUMO energy gap, vertical ionization potential, vertical electron affinity, and chemical hardness for the energetic favorable C(₃₆-n) Si(n) geometries were computed and analyzed. In addition, the aromatic property of C(₃₆-n) Si(n) cagelike clusters was investigated, and the result demonstrate that these C(₃₆-n) Si(n) cagelike structures possess strong aromaticity.
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Affiliation(s)
- Shu-Wei Tang
- Institute of Functional Material Chemistry, Faculty of Chemistry, Northeast Normal University, Changchun, Jilin, 130024, China
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Bomble L, Steinmann SN, Perez-Peralta N, Merino G, Corminboeuf C. Bonding analysis of planar hypercoordinate atoms via the generalized BLW-LOL. J Comput Chem 2013; 34:2242-8. [DOI: 10.1002/jcc.23383] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Revised: 06/16/2013] [Accepted: 06/26/2013] [Indexed: 01/11/2023]
Affiliation(s)
- Laetitia Bomble
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne; 1015; Lausanne; Switzerland
| | - Stephan N. Steinmann
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne; 1015; Lausanne; Switzerland
| | | | - Gabriel Merino
- Departamento de Física Aplicada; Centro de Investigación de Estudios Avanzados; Mérida; Yucatán; 97310; Mexico
| | - Clemence Corminboeuf
- Institut des Sciences et Ingénierie Chimiques; Ecole Polytechnique Fédérale de Lausanne; 1015; Lausanne; Switzerland
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A comparative study of the aromaticity of pyrrole, furan, thiophene, and their aza-derivatives. J Mol Model 2013; 19:3529-35. [PMID: 23716174 DOI: 10.1007/s00894-013-1877-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 04/30/2013] [Indexed: 11/27/2022]
Abstract
The relative aromaticity of pyrrole, furan, thiophene, and their aza-derivatives has been examined using TRE (topological resonance energy), MRE (magnetic resonance energy), ring current (RC), and ring current diamagnetic susceptibility (χG) methods. The results obtained were compared with results obtained by others who used the energetic method ASE (aromatic stabilization energy), the geometric method HOMA (harmonic oscillator model of aromaticity), and the magnetic method NICS(1) (nucleus-independent chemical shift). The impact of nitrogen atoms on the aromaticity of the aza-derivatives of pyrrole, furan, and thiophene is discussed. An excellent correlation was found between the energetic (TRE, MRE) and magnetic (RC and χG) criteria of aromaticity for all compounds. It was expected that inclusion of a heteroatom would decrease the aromaticity relative to the cyclopentadienyl anion. Our results show that the type of the first heteroatom, which donates two electrons to the system, as well as the number of nitrogen atoms and their positions in the molecule have a strong effect on aromaticity. In general, aromaticity is enhanced when the nitrogen atom is adjacent to the first heteroatom. The magnitude of aromaticity is related closely with the uniformity of distribution of π-electrons in the molecule.
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Wu JI, Fernández I, Mo Y, Schleyer PVR. Why Cyclooctatetraene Is Highly Stabilized: The Importance of "Two-Way" (Double) Hyperconjugation. J Chem Theory Comput 2012; 8:1280-7. [PMID: 26596744 DOI: 10.1021/ct3000553] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Despite its highly nonplanar geometry, the tub-shaped D2d cyclooctatetraene (COT) minimum is far from being an unconjugated polyene model devoid of important π interactions. The warped skeleton of D2d COT results in the large stabilization (41.1 kcal/mol) revealed by its isodesmic bond separation energy (BSE). This originates largely from the "two-way" hyperconjugation, back and forth across the C-C single bonds, between the CC/CH σ(σ*) and the C═C (π*)π orbitals. These hyperconjugative effects compensate for the substantial, but not complete, loss of π conjugation upon ring puckering. C-C single bond rotation of 1,3-butadiene involves a similar interplay between π conjugation and "two-way" double hyperconjugation and serves as a simple model for the inversion of D2d to D4h COT. The perpendicular rotational transition states of many other systems, e.g., the allyl cation, styrene, biphenyl, and ethene, are stabilized similarly by "two-way" hyperconjugation.
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Affiliation(s)
- Judy I Wu
- Department of Chemistry, University of Georgia , Athens, Georgia 30602, United States
| | - Israel Fernández
- Departamento de Química Orgánica, Facultad de Ciencias Químicas, Universidad Complutense Madrid , 28040, Madrid, Spain
| | - Yirong Mo
- Department of Chemistry, Western Michigan University , Kalamazoo, Michigan 49008, United States
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Wu YB, Duan Y, Lu G, Lu HG, Yang P, Schleyer PVR, Merino G, Islas R, Wang ZX. D3h CN3Be3+ and CO3Li3+: viable planar hexacoordinate carbon prototypes. Phys Chem Chem Phys 2012; 14:14760-3. [DOI: 10.1039/c2cp41822c] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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